Immersion boiler



June 8, 1943.

o. N. SELLERS 1 2,321,109

IMMERSION BOILER Filed Aug. 1, 1938 Mara $71 Griz/'72 f 56/ 5676:

Patented June 8, 1943 UNITED STATES PATENT OFFICE IMMERSION BOILER ()rlin N. Sellers, Chicago, 111.

Application August 1, 1938, Serial. No. 222,408

1 Claim.

proportions and, accordingly, no excess air passes through the boiler and no gas is wasted. My improved boiler has a low water line and, accordingly, permits the direct return of condensate without the employment of traps and pumps. The boiler has been found to be highly satisfactory for use with steam jacketed kettles, pressing machines, wax pans, hydraulic presses and Vulcanizing moulds, and other uses will be readily apparent to those skilled in the art. A further feature is the provision of a large steam liberation surface, thu eliminating surging and throwing of water into the steam chamber.

A further object of the invention is the provision of a boiler in which the possibility of tube corrosion and failure is minimized. All the tubes and heating surfaces in my improved boiler are below the water line, and since the lower water zone is not highly heated, an area is :provided for the settling of lime and mud below the heating tubes without the formation of a hard scale which tends to weaken and corrode the tubes.

A further object of the invention is the provision of a boiler of the type described which may be readily and inexpensively manufactured, and the operation of which is automatically controlled without danger of explosion and which is adapted to operate without the usual noise of combustion in boilers of this type.

The invention will be readily understood from the following description in conjunction with the accompanying drawing wherein a preferred embodiment of the invention is shown, in which:

Fig. l is a side elevational view of my improved boiler, partly in section; and

Fig. 2, a vertical sectional view, taken along the lines 22 of Fig. 1.

Referring to the drawing, the reference character 5 indicates a cylindrical shell, which may be formed of steel, mounted on supports 6, 1 and provided with a front head plate 8, a rear head plate 9 and a dished plate l forming a header compartment ll between the plates 9 and ID. The bottom of the shell is provided with a plurality of openings in which are det'acha-bly secured water-tight hand plates [2 and also one or more apertures adapted to receive blow-downlines l3.

A plurality of small firing tubes [4 are horizontally disposed in an intermediate portion of the shell 5 and are carried by and extend through the front and rear head plates 8 and 9. As shown, the firing tubes are disposed in three banks, each bank having six tubes, but it is to be understood that the number and disposition of the tubes may be varied within wide limits. Below the firing tubes are disposed two or more return pass tubes l5 of greater cross section and likewise carried and extending through the front and rear end" plates 8 and 9. The number and size of the tubes I5 maylikewise be varied. As indicated by the arrows in Fig. 1, gases are burned in and pass through the small firing tubes hi into the header chamber ll where they are deflected downwardly and returned through the large tubes 15 .into an exhaust manifold I1, whence they are directed to the stack 18. The return pass tubes 15 are preferably spaced above the bottom of the shell 5, forming a sedimentation zone 19 below the tubes.

As indicated in Fig. l, the firing tubes l4 are completely immersed in water, and the water level is preferably only a slight distance above the upper .bank of tubes in order that steam may be rapidly generated and in order that the maximum amount of heat may be procured along the surface of the water. To maintain the water level, an automatic feed water control 20 of any conventional and well-known type is carried in the feed water line 2|. One or more steam outlets 22 extend through the upper surface of the shell 5. A pop-ofi valve 23 and an automatic pressure control device 24, adapted to stop the operation of the blower 33 when the desired steam pressure is obtained, are likewise mounted on the upper surface of the shell 5. My improved boiler is also preferably provided with a pressure gauge 25, a water column 26, gauge glass 21 and try cocks 28.

A plurality of burners 29 leading from the manifold 30 are disposed adjacent the openings of each firing tube I4. The burners are adapted to form along needle-shaped flame which may extend upwardly of thirty inches within the firing tubes without the usual noise of combustion. The reducing zone of the needle-shaped flame extends in the same horizontal plane as the walls of the tubes, and, accordingly, the oxidizing portion of the flame does not come in contact with the metallic tube Walls. Pilots 3| leading from a gas supply line 32 are disposed between the banks of burners and are preferably provided with an automatic safety pilot (not shown) of any conventional well-known type adapted to cut off the main gas supply in case the pilot flame is extinguished for any reason.

In order to supply a combustible gas under pressure to the burners, a blower 33 provides air under suiiicient pressure and furnishes it to the mixing chamber 34 where it is mixed with gas in the desired proportions from the gas supply line 35 and is then forced in the form of a blast to the manifold 30 and the burners 29. A hand operated valve 36 may be interposed in the gas supply line 35.

The boiler is provided with an improved safety device in the form of a delay switch providing a positive control upon the main gas supply line. A line 31 leads from the air supply line of the blower to a disc-like chamber 38 containing a diaphragm 39 upon the upper surface of which is mounted a pin 40. When air under pressure is supplied to the diaphragm, the pin 40 is raised, contacting an arm 4| of a mercury switch 42 and closing the switch. The switch 42 is electrically connected in series by leads 43 (shown broken in Fig. 2) to a magnetic gas valve 44 equipped with a solenoid and disposed in the gas supply line 35. A spring 45 urges the switch 42 to an open position when the pin 40 and arm 4| of the switch are out of engagement. When the switch 42 is opened, the magnetic gas valve 44 is closed. Thus it will be seen that gas is not supplied to the burners when the blower is not in operation, and upon the initial operation of the boiler a charge of pure air is first blown through the firing tubes I 4 to remove any impure gases. Shortly after this initial blast of air the mercury switch 42 is closed in the manner described, opening the magnetic valve 44 in the gas line and supplying gas to the manifold 30. When the blower is shut off by the automatic pressure control 24, the magnetic valve 44 is automatically closed by the release of the pin 40 when the diaphragm 39 returns to its normal position, opening the mercury switch 42. Accordingly, since air pressure from the blower 33 is necessary to close switch 42, opening valve 44, it is apparent that gas cannot be supplied to burners 29, unless the blower is in operation, thereby providing a poistive safety control.

From the foregoing it will be apparent that high combustion efficiency is obtained in my improved boiler, since the gas flames extend an appreciable distance into the firing tubes l4, and that the upper bank of firing tubes are just below the water level. Furthermore, the flue gases make two complete passes through the boiler and in returning appreciably heat the water in the lower portion of the boiler.

The foregoing detailed description has been given to illustrate a preferred embodiment of the invention and for clearness of understanding only, and no unnecessary limitations should be understood therefrom.

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent is:

A gas fired boiler of the immersion type having, in combination, a water and steam compartment and a plurality of small diameter firing tubes and return tubes of greater diameter than said firing tubes; within said water compartment; burners disposed adjacent the openings of said firing tubes and adapted to project flames into an intermediate portion of said firing tubes, a manifold connecting said burners and a gas supply line, a magnetic valve in said gas supply line, an air supply line including a, blower adapted to supply air under pressure to said manifold, and a'mercury switch adapted to cause a closing of said magnetic valve upon less than a predeter mined amount of airflowing through said air supply line and equipped with a diaphragm responsive to the movement of air through said air supply line,

ORLIN N. SELLERS. 

